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https://www.readbyqxmd.com/read/28535054/tuning-the-binding-dynamics-of-a-guest-octaacid-capsule-through-non-covalent-anchoring
#1
Suma S Thomas, Hao Tang, Adam Gaudes, Signe B Baggesen, Corinne L D Gibb, Bruce C Gibb, Cornelia Bohne
Hydrophobic or hydrophilic substituents have different effects on the binding dynamics of pyrene derivatives with a 2:1 capsule formed from two octaacid cavitands, showing a subtle interplay of different kinetic factors. Anchoring of the methyl group of 1-methylpyrene within one cavitand slowed the association and dissociation dynamics of the 1:1 complex by at least 1,000 times when compared to the 1:1 complex for pyrene. This slow down for the transient formation of the 1:1 complex is responsible for the overall increase in stability of the 2:1 complex without affecting the overall capsule dissociation...
May 23, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28535040/cancer-cell-discrimination-using-host-guest-doubled-arrays
#2
Ngoc D B Le, Gulen Yesilbag Tonga, Rubul Mout, Sung Tae Kim, Marcos E Wille, Subinoy Rana, Karen A Dunphy, D Joseph Jerry, Mahdieh Yazdani, Rajesh Ramanathan, Caren M Rotello, Vincent M Rotello
We report a nanosensor that uses cell lysates to rapidly profile the tumorigenicity of cancer cells. This sensing platform uses host-guest interactions between cucurbit[7]uril (CB[7]) and the cationic headgroup of a gold nanoparticle (AuNP) to non-covalently modify the binding of three fluorescent proteins of a multichannel sensor in situ. This approach doubles the number of output channels to six, providing single-well identification of cell lysates with 100 % accuracy. Significantly, this classification could be extended beyond the training set, determining the invasiveness of novel cell lines...
May 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28534917/charge-stabilizing-tris-triphenylamine-zinc-porphyrin-carbon-nanotube-hybrids-synthesis-characterization-and-excited-state-charge-transfer-studies
#3
Luis M Arellano, Myriam Barrejón, Habtom B Gobeze, María J Gómez-Escalonilla, José Luis G Fierro, Francis D'Souza, Fernando Langa
Functionalization of single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) with a charge stabilizing zinc porphyrin functionalized with triphenylamine entities has been accomplished. The synthetic approach involved the reaction of tris-(triphenylamine)porphyrinato zinc(ii) with iodobenzene functionalized nanotubes through a Sonogashira C-C cross coupling reaction under microwave irradiation conditions. Evidence of covalent functionalization and the extent of functionalization was obtained from systematic studies carried out by AFM, TGA, XPS and Raman spectroscopy techniques...
May 23, 2017: Nanoscale
https://www.readbyqxmd.com/read/28534914/covalent-inhibition-of-protein-tyrosine-phosphatases
#4
REVIEW
Kasi Viswanatharaju Ruddraraju, Zhong-Yin Zhang
Protein tyrosine phosphatases (PTPs) are a large family of 107 signaling enzymes that catalyze the hydrolytic removal of phosphate groups from tyrosine residues in a target protein. The phosphorylation status of tyrosine residues on proteins serve as a ubiquitous mechanism for cellular signal transduction. Aberrant function of PTPs can lead to many human diseases, such as diabetes, obesity, cancer, and autoimmune diseases. As the number of disease relevant PTPs increases, there is urgency in developing highly potent inhibitors that are selective towards specific PTPs...
May 23, 2017: Molecular BioSystems
https://www.readbyqxmd.com/read/28534525/covalently-linked-dengue-virus-envelope-glycoprotein-dimers-reduce-exposure-of-the-immunodominant-fusion-loop-epitope
#5
Alexander Rouvinski, Wanwisa Dejnirattisai, Pablo Guardado-Calvo, Marie-Christine Vaney, Arvind Sharma, Stéphane Duquerroy, Piyada Supasa, Wiyada Wongwiwat, Ahmed Haouz, Giovanna Barba-Spaeth, Juthathip Mongkolsapaya, Félix A Rey, Gavin R Screaton
A problem in the search for an efficient vaccine against dengue virus is the immunodominance of the fusion loop epitope (FLE), a segment of the envelope protein E that is buried at the interface of the E dimers coating mature viral particles. Anti-FLE antibodies are broadly cross-reactive but poorly neutralizing, displaying a strong infection enhancing potential. FLE exposure takes place via dynamic 'breathing' of E dimers at the virion surface. In contrast, antibodies targeting the E dimer epitope (EDE), readily exposed at the E dimer interface over the region of the conserved fusion loop, are very potent and broadly neutralizing...
May 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28533376/b12-dependent-photoresponsive-protein-hydrogels-for-controlled-stem-cell-protein-release
#6
Ri Wang, Zhongguang Yang, Jiren Luo, I-Ming Hsing, Fei Sun
Thanks to the precise control over their structural and functional properties, genetically engineered protein-based hydrogels have emerged as a promising candidate for biomedical applications. Given the growing demand for creating stimuli-responsive "smart" hydrogels, here we show the synthesis of entirely protein-based photoresponsive hydrogels by covalently polymerizing the adenosylcobalamin (AdoB12)-dependent photoreceptor C-terminal adenosylcobalamin binding domain (CarHC) proteins using genetically encoded SpyTag-SpyCatcher chemistry under mild physiological conditions...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28533375/keap1-modifying-small-molecule-reveals-muted-nrf2-signaling-responses-in-neural-stem-cells-from-huntington-s-disease-patients
#7
Luisa Quinti, Sharadha Dayalan Naidu, Ulrike Träger, Xiqun Chen, Kimberly Kegel-Gleason, David Llères, Colúm Connolly, Vanita Chopra, Cho Low, Sébastien Moniot, Ellen Sapp, Adelaide R Tousley, Petr Vodicka, Michael J Van Kanegan, Linda S Kaltenbach, Lisa A Crawford, Matthew Fuszard, Maureen Higgins, James R C Miller, Ruth E Farmer, Vijay Potluri, Susanta Samajdar, Lisa Meisel, Ningzhe Zhang, Andrew Snyder, Ross Stein, Steven M Hersch, Lisa M Ellerby, Eranthie Weerapana, Michael A Schwarzschild, Clemens Steegborn, Blair R Leavitt, Alexei Degterev, Sarah J Tabrizi, Donald C Lo, Marian DiFiglia, Leslie M Thompson, Albena T Dinkova-Kostova, Aleksey G Kazantsev
The activity of the transcription factor nuclear factor-erythroid 2 p45-derived factor 2 (NRF2) is orchestrated and amplified through enhanced transcription of antioxidant and antiinflammatory target genes. The present study has characterized a triazole-containing inducer of NRF2 and elucidated the mechanism by which this molecule activates NRF2 signaling. In a highly selective manner, the compound covalently modifies a critical stress-sensor cysteine (C151) of the E3 ligase substrate adaptor protein Kelch-like ECH-associated protein 1 (KEAP1), the primary negative regulator of NRF2...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28533368/bio-inspired-self-healing-structural-color-hydrogel
#8
Fanfan Fu, Zhuoyue Chen, Ze Zhao, Huan Wang, Luoran Shang, Zhongze Gu, Yuanjin Zhao
Biologically inspired self-healing structural color hydrogels were developed by adding a glucose oxidase (GOX)- and catalase (CAT)-filled glutaraldehyde cross-linked BSA hydrogel into methacrylated gelatin (GelMA) inverse opal scaffolds. The composite hydrogel materials with the polymerized GelMA scaffold could maintain the stability of an inverse opal structure and its resultant structural colors, whereas the protein hydrogel filler could impart self-healing capability through the reversible covalent attachment of glutaraldehyde to lysine residues of BSA and enzyme additives...
May 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28532685/nitroxide-4-hydroxy-2-2-6-6-tetramethylpiperidine-1-oxyl-tempol-inhibits-the-reductase-activity-of-protein-disulfide-isomerase-via-covalent-binding-to-the-cys400-residue-on-cxxc-redox-motif-at-the-a-active-site
#9
Gérsika Bitencourt Santos, Lucia Gonzalez-Perilli, Mauricio Mastrogiovanni, Adrián Aicardo, Cláudio Daniel Cerdeira, Andrés Trostchansky, Maísa Ribeiro Pereira Lima Brigagão
BACKGROUND AND AIM: Oxidative stress arising from inflammatory processes is a serious cause of cell and tissue damage. Tempol is an efficient antioxidant with superoxide dismutase-like activity. The purpose of this paper is to address the inhibition of protein disulfide isomerase (PDI), an essential redox chaperone whose active sites contain the Cys-Gly-His-Cys (CXXC) motif, by the nitroxide Tempol. RESULTS: In the presence of Tempol (5-120 μM), the reductase activity of PDI was reversibly affected both in vitro and in activated mice neutrophils, with an IC50 of 22...
May 19, 2017: Chemico-biological Interactions
https://www.readbyqxmd.com/read/28532223/preliminary-study-on-fabrication-characterization-and-synergistic-anti-lung-cancer-effects-of-self-assembled-micelles-of-covalently-conjugated-celastrol-polyethylene-glycol-ginsenoside-rh2
#10
Peng Li, XiaoYue Zhou, Ding Qu, Mengfei Guo, Chenyi Fan, Tong Zhou, Yang Ling
The aim of this study was to develop an amphipathic polyethylene glycol (PEG) derivative that was bi-terminally modified with celastrol and ginsenoside Rh2 (Celastrol-PEG-G Rh2). Such derivative was capable of forming novel, celastrol-loaded polymeric micelles (CG-M) for endo/lysosomal delivery and thereby synergistic treatment of lung cancer. Celastrol-PEG-G Rh2 with a yield of 55.6% was first synthesized and characterized. Its critical micellar concentration was 1 × 10(-5 )M, determined by pyrene entrapment method...
November 2017: Drug Delivery
https://www.readbyqxmd.com/read/28532097/influence-of-telopeptides-on-the-structural-and-physical-properties-of-polymeric-and-monomeric-acid-soluble-type-i-collagen
#11
Róisín Holmes, Steve Kirk, Giuseppe Tronci, Xuebin Yang, David Wood
Currently two factors hinder the use of collagen as building block of regenerative devices: the limited mechanical strength in aqueous environment, and potential antigenicity. Polymeric collagen is naturally found in the cross-linked state and is mechanically tougher than the monomeric, acid-soluble collagen ex vivo. The antigenicity of collagen, on the other hand, is mainly ascribed to inter-species variations in amino acid sequences of the non-helical terminal telopeptides. These telopeptides can be removed through enzymatic treatment to produce atelocollagen, although the effect of this cleavage on triple helix organization, amino acidic composition and thermal properties is often disregarded...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532078/enhancement-of-fibroblast-growing-on-the-mannosylated-surface-of-cellulose-membranes
#12
Simone Birkheur, Paula Cristina de Sousa Faria-Tischer, Cesar A Tischer, Elisângela Flávia Pimentel, Marcio Fronza, Denise Coutinho Endringer, Anna Paola Butera, Renato Márcio Ribeiro-Viana
Bacterial cellulose membrane is a biomaterial with high value in the biomedical field. Many groups have been making efforts to promote chemical modifications of its structure and, consequently, add new characteristics. Recently, our group has developed a methodology to insert monoester succinic acid in bacterial cellulose membrane without disrupting the microfibril network and bind a protein on it. Considering the role of carbohydrates in the molecular recognition process in biological events, we continued these studies by inserting covalently multiples copies of aryl monosaccharide to bacterial cellulose succinylated and to study the in vitro tissue compatibility using fibroblasts...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532053/functionalized-fe3o4-graphene-oxide-nanocomposites-with-hairpin-aptamers-for-the-separation-and-preconcentration-of-trace-pb-2-from-biological-samples-prior-to-determination-by-icp-ms
#13
Mojtaba Shamsipur, Leila Farzin, Mahmoud Amouzadeh Tabrizi, Shahab Sheibani
Lead (Pb) as a topically poisonous metal represents a serious threat to the ecological environment and especially to human beings. Therefore, it is urgent to develop a rapid and reliable monitoring technique for this heavy metal in the environmental samples. In the present study, we have designed a selective and sensitive method for the determination of ultratrace contents of Pb(2+) in biological samples, based on the guanine (G)-quadruplex formed by the aptamer with hairpin structure and Pb(2+). For this purpose, Pb(2+) specific aptamer serving as affinity probe to capture and separate trace amounts of the analyte, was covalently linked to Fe3O4/graphene oxide (GO) surface by using a suitable cross-linking agent...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532052/poly-%C3%AE%C2%B5-caprolactone-modification-via-surface-initiated-atom-transfer-radical-polymerization-with-bio-inspired-phosphorylcholine
#14
Liu He, Lei Huang, Songbai Zhang, Yuanwei Chen, Xianglin Luo
Bio-inspired phosphorylcholine modification on material surface has shown great promise in constructing biocompatible materials. In this study, poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was grown on poly(ε-caprolactone) (PCL) surface in order to suppress protein adsorption and cells adhesion and to improve blood compatibility. The initiator for surface initiated atom transfer radical polymerization (SI-ATRP) was covalently tethered on PCL surface and then PMPC brushes with diverse graft amounts were grafted to PCL film...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532038/dynamic-covalent-linked-triblock-copolymer-micelles-for-glutathione-mediated-intracellular-drug-delivery
#15
Xueli Wang, Changyu He, Qinglai Yang, Lianjiang Tan, Bingya Liu, Zhenggang Zhu, Bing Gong, Yu-Mei Shen
Redox-responsive linkages dispersed in the backbones of the synthetic polymers, while young in the current spectrum of the biomedical application, are rapidly extending into their niche. In the present work, triblock copolymer PEG-PLA-PEG synthesized and characterized by (1)H -NMR and SEC can self-assemble into redox-responsive micelles in aqueous media with nanosized 33nm and 47nm. And the copolymers PEG2000-PLA3000-PEG2000 and PEG2000-PLA5000-PEG2000 present lower CMC with 0.034 and 0.022mg/mL, and higher DLC of 4...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532018/characterization-of-physical-and-biodegradation-properties-of-poly-3-hydroxybutyrate-co-3-hydroxyvalerate-sepiolite-nanocomposites
#16
Omer Shakil, Farha Masood, Tariq Yasin
The pristine sepiolite was treated with the 3-aminopropyl triethoxy silane (APTES). The APTES grafted sepiolite (APTES-G-SP) was used to develop the poly-3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV)/sepiolite nanocomposite films by the solution-casting method. Scanning electron micrographs showed that the APTES-G-SP fibers were well embedded in the polymer matrix. Fourier transform Infrared spectroscopy attributed the formation of covalent bonds between the APTES-G-SP and PHBV in the nanocomposite film. Thermal and water-barrier properties of the nanocomposite films were significantly improved...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28532002/electrochemical-sensor-for-detection-of-hydrogen-peroxide-modified-with-prussian-blue-electrodeposition-on-nitrogen-phosphorus-and-sulfur-co-doped-porous-carbons-chitosan
#17
Xiurong Zhai, Yonghong Li, Jisen Li, Chengyang Yue, Xiaowu Lei
Nitrogen, phosphorus and sulfur co-doped porous carbons (N, P, S@PC) were well dispersed in the chitosan (CS) acid solution, in particular via covalently interaction, which could avoid the aggregation of N, P, S@PC in most solvents. Moreover, CS could also avoid N, P, S@PC leakage from the modified electrode. A novel electrochemical sensor was then developed through prussian blue (PB) was electrodeposited on the glass carbon (GC) electrode modified with N, P, S@PC-CS composite. Results with scanning electron microscopy image, illustrate that PB/N, P, S@PC-CS composite distributes very uniformly on the substrate surface, which is hoped to be very attractive for determination of hydrogen peroxide (H2O2)...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531973/properties-and-toughening-mechanisms-of-pva-pam-double-network-hydrogels-prepared-by-freeze-thawing-and-anneal-swelling
#18
Kangkang Ou, Xia Dong, Chengling Qin, Xinan Ji, Jinxin He
It is well known that preparation method of hydrogels has a significant effect on their properties. In this paper, freeze-thawing and anneal-swelling were applied to prepare poly(vinyl alcohol)/polyacrylamide (PVA/PAM) double-network hydrogels with covalently and physically cross-linked networks. The properties of these hydrogels were investigated and compared to control hydrogels. Results indicated that hydrogels fabricated by freeze-thawing show larger pores size and higher swelling capacity than those made by anneal-swelling and control hydrogels...
August 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/28531875/elaboration-of-antibacterial-plastic-surfaces-by-a-combination-of-antiadhesive-and-biocidal-coatings-of-natural-products
#19
Jean-Baptiste Paris, Damien Seyer, Thierry Jouenne, Pascal Thébault
Antibacterial polyolefins surfaces, combining biocidal and antiadhesive properties, were elaborated by a covalent grafting of antimicrobial peptides (AMPs), able to kill adherent bacteria, on a pre-immobilized hyaluronic acid (HA) layer, able to repel the micro-organisms. Different HA activation rate for its immobilization, were used to change HA layer morphology and number of residual free carboxylic acid functions for AMPs grafting. Based on adhesion tests on Staphylococcus epidermidis and microscopy fluorescent observations, the presence of the two combined properties was shown to be depended on the HA activation rate...
May 13, 2017: Colloids and Surfaces. B, Biointerfaces
https://www.readbyqxmd.com/read/28531843/rapid-ic-ms-ms-determination-of-methylphosphonic-acid-in-urine-of-rats-exposed-to-organophosphorus-nerve-agents
#20
Timur Baygildiev, Alexandra Zatirakha, Igor Rodin, Arkady Braun, Andrey Stavrianidi, Nadezhda Koryagina, Igor Rybalchenko, Oleg Shpigun
A direct approach for the determination of a specific hydrolysis product of organophosphorus nerve agents such as methylphosphonic acid (MPA) in urine by ion chromatography and tandem mass spectrometry (IC-MS/MS) has been developed. The first advantage of the proposed approach is a rapid and simple sample preparation, which does not require a large sample volume, complicated and laborious preconcentration and derivatization steps, and takes less than 7min per sample. The second advantage is the fast and selective IC determination of MPA carried out on a noncommercial anion exchanger based on a poly(styrene-co-divinylbenzene) (PS-DVB) substrate with a high degree of crosslinking and a covalently-bonded branched functional layer, which enables complete resolution of MPA from major urine matrix components and allows one to overcome matrix effects...
May 8, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
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